Fuel injector or atomizer for internal combustion engines



NW, 22, 1938. 1-. c. MAKINS 2,137,473

FUEL INJECTOR 0R ATOMIZER FOR INTERNAL COMBUSTION ENGINES Filed Feb. 16,1935 Patented Nov. 1938 I UNITED. STATES FUEL INJECTOR OR ATODIIZER FORINTERNAL COMBUSTION ENGINES Thomas Clifford Makins Llncoln, England, as-

signor to Ruston & Hornsby, Limited, Lincoln,

England Application February 16. 1938, Serial No. 190,837 In GreatBritain December 2, 1936 8Clalms.

This invention relates to fuel injectors or atomizers for airless orsolid injection compression ignition oil engines and particularly tothose of the type in which a spring loaded fuel injection or needlevalve is adapted to be lifted from its seat by the pressure of the fueloil delivered by a pump to open a delivery orifice or orifices throughwhich the fuel passes to the working or combustion chamber of theengine. Injectors or atomizers of this type are described in thespecifications of British Letters Patent No. 20,582 of 1909 and 9,382 of1915.

The object of the present invention is to provide an improved fuelinjector or atomizer of the above type particularly with a view toensuring the accurate seating of the needle valve at all times and alsosimplifying the construction whereby assemblage, removal and replacementof the parts will be facilitated.

According to one feature of the present invention, the needle valveseats in a sleeve which is closed at its inner end to form anozzlehaving a suitable delivery aperture or apertures and is mounted inthe bore of the injector or atomizer body at the delivery end with asmall clearance, the construction and arrangement being such that inassembling the parts, as the loading spring is being placed in position,the pressure it exerts upon the needle valve thrusts the latter on toits seat so that if the latter is not central with the valve the seatingsleeve is adjusted automatically by the valve itself so as to seat thevalve accurately, whilst the engaging surfaces between the seatingsleeve and the interior of the injector or atomizer body" permit theseating sleeve to be held firmly in its correct position for seating thevalve accurately upon pressure being applied to it solely in a directionparallel with the axis of the valve in subsequently securing the seatingsleeve in position, whereby accurate seating of the valve will beeifected automatically.

Preferably, the inner end of a cartridge sleeve fitting without play butremovably secured within the atomizer body or casing and housing thesliding needle valve, bears against the said valve seating member, theengaging surfaces between the cartridge sleeve and the seating sleeve aswell as those between the latter and the interior of the body of theinjector or atomizer permitting the pressure for securing the seatingsleeve in its correct position for seating the valve accurately, to beapplied through the cartridge sleeve parallel with the axis of thevalve.

Where the lift of the needle valve is limited by a stop pin or peg, Iprefer to arrange this to project into the outer part oi. the cartridgesleeve with its head held hard against the outer edge of the latter,preferably by a plug screwed into the outer end of the body or casing ofthe injectorlor atomizer, and with the engaging surfaces fittingsquarely one against the other.

According to another feature of the present invention, a readilyremovable cartridge sleeve which bears upon a seating sleeve closed atits inner end to form a nozzle having a suitable de- 1 livery apertureor apertures and mounted at the delivery end of the body of the injectoror atomizer, houses in addition to the piston of the needle valve, astop pin or peg for limiting the lift of said valve, and also theloading spring,

so that the whole of these parts can be assembled in-the body or casingof the injector or atomizer as a single unit, whereupon the unit isadapted to be secured in. position preferably through the head of thestop pin or peg, as by a plug screwed into the outer end of the body orcasing of the injector or atomizer.

Preferably, a loose disc is fitted within the cartridge sleeve betweenthe outer end or top of the piston 01' the needle valve and the innerend of the stop pin, whereby the lift of said valve may be veryaccurately determined by suitably reducing the thickness of the disc orsubstituting a disc of the required thickness as found necessary, whilstthe atomizer spring which encircles the stoppin and bears at its outerend preferably against the head of the latter, bears at its inner endagainst said disc, thereby obviating the transmission of side thrust tothe needle valve by the spring.

Fuel oil is delivered to the piston of the needle valve through alongitudinal passage or passages formed by providing a channel,channels, groove or grooves in either the outer periphery of thecartridge sleeve or the inner periphery of the injector or atomizer bodyor casing or partly in one and partly in the other, and also through oneor more inwardly directed channels, passages or ducts formed preferablyat or near the inner edge of the cartridge sleeve.

To permit any oil that may leak past the piston of the needle valve toescape freely, I prefer to bore an inclined hole or holes from the inneror under face of the head of the stop pin or peg, preferably on a centreline or lines passing through the annular edge between the said inner orunder face of the head of the stop pin or peg and the periphery of thelatter, to an axial or longitudinal bore or passage in said head, whichs in communication with a bore or passage through a plug screwed intothe outer end of the bore of the atomizer or injector body'or casinghard against the said head.

The accompanying drawing shows two forms of atomizer according to thepresent invention, Figure 1 being an axial vertical sectional elevationof one form and Figure 2 a sectional elevation ofa modifled form ofnozzle.

In carrying out the present invention as illustrated in Figure 1, thebody I of the atomizer is bored longitudinally from end to end with astepped down portion near the nozzle end where a flanged seating sleeve2 is fitted with a small clearance at I and with its flange 4 fittingagainst the annular flat shoulder 5 formed between the two diameters 6and 1 of the said bore. The inner end of the seating sleeve 2 is closedto form an integral nozzle portion having delivery apertures or orifices24. A cartridge sleeve 8 is made a sliding fit in the main or largerbore 8 of the atomizer body I with its inner end bearing at 9 upon theouter face of the flange 4 of the seating sleeve 2. The inner endportion of the cartridge sleeve is bored at III to receive thepiston'portion ll of the needle valve I2, whilst the outer end portionis formed of much larger internal diameter at l2 than the lower portionand is preferably machined. Upon the outer edge l4 of the cartridgesleeve bears the inner or under side I! of the head I of a stop pin orpeg H which projects axially into the outer end portion of the cartridgesleeve with its inner end disposed near to the outer end of the needlevalve. A plug i8 screwed into the outer end of the atomizer casing Iagainst the head It of the stop pin I! through a copper packing ring l9,binds said head hard against the outer edge of the cartridge sleevewhich in turn bears at its inner end 9 hard against the flange 4 of theseating sleeve 2 in order to maintain the latter in position. A loosedisc 20 is fitted within the outer end portion of the cartridge sleevebetween the outer end of the piston portion ll of the needle valve l2and the inner end 2| of the stop pin or peg with a predeterminedclearance and between this disc 20 and the inner or under side l5 of thehead of the stop pin or peg ii the spring 22 of the needle valve I2 isarranged about the stop pin itself.

Fuel is admitted preferably towards the outer end of the atomizer bodythrough an edge type fllter l2 mountedin a filter body 33 which isscrewed into a socket of the atomizer body and is disposed parallel withthe axis of and closely adjacent the latter. The filter may however bearranged at right angles to the atomizer body. A fllter of the edge typeis described in the provisional specification of my co-pendingapplication for British Letters Patent No. 466 of 1937. After leavingthe edge filter 22, the fuel passes through a passage 23 to a point atthe outer end of the cartridge sleeve 8 and in order to convey it fromthere to the inner or under side of the piston portion I i of the needlevalve, one or more straight longitudinal grooves 24 is or are-cut in theexterior periphery of the cartridge sleeve and communicating therewithis or are a groove or grooves 25 disposed at the inner end of thecartridge sleeve and opening into the interior of the latter. Instead ofthe groove or grooves 2|, a port or ports may be providedin thecartridge sleeve 8. Where more than one longitudinal groove 24 isprovided as illustrated, communication between these grooves and thefuel inlet is effected through an annular chamber 26 formed beyond theouter end of the cartridge sleeve between the bore 6 of the atomizerbody and a reduced part 21 of the head of the stop pin H.

To permit fuel oil that may lead past the needle valve l2 to escapefreely from the atomizer, inclined holes 28 are bored on centre linespassing through the annular edge 28 between the inner or under side lbof the head ii of the stop pin or peg l1 and the periphery of thelatter, to the coned end of an axial hole 30 in the head it.

The bore 30 is screw threaded to permit the in-' sertion of a suitabletool for removing the head I and stop pin or peg l1 when required as forinspection or replacement of parts. The adjacent plug it screwed intothe outer end of the atomizer body I is similarly provided with acentral bore ii.

In Figure 2 the valve is of pintle form, that is to say the coned face35 of the valve is extended beyond the sleeve 2 to provide another andinverted cone 31, of which the shape determines the angle of spray.Between the two coned faces is a cylindrical portion 38, shaped toprovide a minimum clearance with the sleeve 2, to avoid the formation ofcarbon deposits. It will be seen that the angle of the coned face 35does not coincide with the seat Bil-the diflerence in angles beinghowever very slight. This difference in angle allows the valve to closemore readily, as theoretically the valve seats along a circular line. Ifit seated all along the coned face 36 the pressure of the fuel wouldhave to act along the whole of the face 38 against the loading springpressure tending to hold the valve closed.

With the foregoing constructions and arrangements, it will be understoodthat in assembling the parts, the pressure of the loading spring 22 uponthe piston portion ll of the needle valve l2 causes the face 35 of thelatter, which is coned at an acute angle, to bear hard upon its seat 36so that if it does not then seat accurately, it adjusts the position ofthe seating sleeve 2 automatically to bring about accurate seating. Uponsubsequently securing the stop pin I! in position by the screwed plug[8, the seating sleeve 2 will be firmly secured in its adjusted orcorrect position for seating the needle valve l2 accurately. To ensurethat the seating sleeve 2 will not be shifted from that position duringsaid securing operation, the engaging surfaces l4 and I5 between thehead l6 of the stop pin l1 and the cartridge sleeve 8, between thelatter and the flange 4 of the seating sleeve 2 and also between thelatter and the annular flat shoulder 5 within the atomizer body, areaccurately machined to fit squarely one against the other. In replacingthe parts after cleaning for example, the accurate seating of the needlevalve l2 will be ensured thereby maintaining the efficiency of theatomizer and obviating any increase in the fuel consumption of theengine to which it is applied, contrary to the case of knownconstructions of fuel atomizer.

Furthermore, wear between the piston portion ll of the sliding needlevalve l2 and the cartridge sleeve 8 will be lessened as the loose disc20 obviates the transmission of lateral pressure to the needle valve l2by the loading spring 22. Again, in the case of wear, replacement of thecartridge sleeve 8 can be readily carried out at small cost and withoutaffecting the adjusting of the valve seating sleeve 2 automatically whenreassembling the parts.

According to modifications of the construction particularly describedabove, the longitudinal groove or grooves for conveying the fuel oilfrom the inlet, may be provided in the interior periphery of theinjector or atomizer body or partly in the latter and partly in theexterior periphery of the cartridge sleeve. Furthermore, instead of acentral bore in the head of the stop pin and through the said securingplug, I may provide each of these members with a longitudinal passage orpassages arranged otherwise. Again, communication between the centralbore or other longitudinal passage or passages through the said securingplug and the interior of the outer portion of the cartridge sleeve, maybe eflected through one or more holes drilled from the inner end to theouter end of the head of the stop pin or vice versa. Although I preferto construct the head of the stop pin or peg with its inner or underface flush with the outer edge or top of the cartridge sleeve, I may insome cases construct said head so that it projects and fits into theouter or upper part of the cartridge sleeve for a predetermined distanceand provide for the escape of any fuel oil that may leak past the pistonof the needle valve by forming on or in the exterior of that part of thesaid head that fits into the cartridge sleeve, a flat, flats, groove orrooves communicating through an inwardly or radially directed hole orholes with an axial or longitudinal bore or passage in said head fromwhich the leakage of fuel oil passes through the hollow plug screwedinto the outer end of the bore of the injector or atomizer body orcasing.

What I claim is:

1. An atomizer comprising a casing, a nozzle member and a valve axiallymovable with respect to said nozzle member, the nozzle member providinga seating for said valve and being mounted in the casing so that duringassembly it has freedom of lateral movement to enable the valve to beproperly registered with respect to its seating, and means for clampingthe nozzle member in the position of proper registration.

2. An atomizer comprising a casing, a nozzle member supported withlateral clearance in the casing, a valve axially movable in the nozzlemember, and nozzle member providing a seating for the valve, saidlateral clearance enabling movement of the nozzle member to effect,during assembly, correct registration of the valve with respect to itsseating, a thrust member mounted for axial movement in said casing, andmeans for clamping the said nozzle member in position through theintermediary of said thrust member.

3. An atomizer comprising a casing, a nozzle member supported loosely insaid casing and providing a seating for a valve, a clamping device, athrust member intermediate said nozzle member and said device, a valvehaving a piston portion housed and guided in said thrust member, andresilient means urging said valve on to its seating, the arrangementbeing such that the clamping device in one part of its movement operatesupon the resilient means and in a subsequent part of its movement uponsaid thrust member.

4. A fuel atomizer comprising a casing, a nozzle member supportedloosely in said casing and providing a seating for a valve, a clampingdevice, a thrust member slidably mounted in said casing intermediatesaid nozzle member and said device, a valve having a piston portionslidably housed in said thrust member, and resilient means housed insaid thrust member for urging said valve on to its seating, thearrangement being such that the clamping device in one part of itsmovement operates on the resilient means and in a subsequent part of itsmovement on said thrust member, said thrust member being so arrangedwith respect to the casing as to leave therebetween fuel ducts, leadingto said valve, said clamping device being bored to provide a fuel leakpassage.

5. An atomizer comprising a casing, a nozzle member mounted with lateralclearance in said casing and providing a seating for a valve, a

clamping device, a thrust member slidably mount-' ed in said casingintermediate said nozzle member and said clamping device, a valve havinga piston portion slidably housed and guided in said thrust member, acompression spring housed in said thrust member, a plug member slidablymounted in said casing intermediate said thrust member and said clampingdevice, the whole arrangement being such that said clamping deviceinitially operates on said valve through the intermediary of the springand plug member, and subsequently on said nozzle member through theintermediary of said thrust member and plug member.

6. An atomizer comprising a casing, a nozzle member mounted with lateralclearance insaid casing and providing a seating for a valve, a clampingdevice, a thrust member slidably mounted in said casing intermediatesaid nozzle member and said clamping device, a valve having a pistonportion slidably housed and guided in said thrust member, a compressionspring housed in said thrust member, a plug member slidably mounted insaid casing intermediate said thrust member and said clamping device, astop pin on said plug member extending into said thrust member, a loosedisc between said spring and said piston portion, said pin limiting thelift of said valve by contacting with said disc, the whole arrangementbeing such that during assembly said clamping device in its clampingmovement initially operates on said valve through the intermediary ofthe spring and plug member, and subsequently on said nozzle memberthrough the intermediary of said thrust member and plug member.

'7. An atomizer comprising a casing, a ledge within said casing at rightangles to the axis thereof, a nozzle member fitting with lateralclearance within said casing, a flange on said member fitting withlateral clearance within said casing and seating on said ledge, aseating for a valve within the nozzle member, a thrust member mountedfor axial movement in the said casing, a valve mounted for longitudinalmovement, a piston portion on said valve slidably guided in said thrustmember, resilient means for urging said valve axially into engagementwith said seating, said lateral clearances allowing movement of saidnozzle member to enable the valve to be properly registered with respectto its seating and a clamping device for moving said thrust memberaxially into contact with said flange to hold said nozzle member firmlyin such position of proper registration.

8. A fuel atomizer comprising a hollow casing, a ledge within saidcasing providing a step down boring in said casing a nozzle memberfitting with lateral clearance within the smaller bore of said casing, aflange on said member fitting with lateral clearance within the largerbore of said cassaid thrust member, a disc loosely mounted in saidthrust member between said spring and piston portion, a plug memberslidably mounted in said casing intermediate said clamping device andsaid thrust member, a stop pin on said plug member extending into saidthrust member, said clamping device during assembly operating on saidvalve to register it with its seating through the intermediary oi' theplug member and compression spring, and subsequently on said nozzlemember to hold it correctly positioned through the intermediary of saidplug and thrust member, said thrust member being so arranged within saidcasing as to leave therebetween fuel ducts leading to said valve.

THOMAS CLIFFORD MAKINS.

